alistair23-linux/tools/perf/Documentation/perf-kmem.txt
David Ahern 2a865bd8dd perf kmem: Add option to specify time window of interest
Add option to allow user to control analysis window. e.g., collect data
for time window and analyze a segment of interest within that window.

Committer notes:

Testing it:

  # perf kmem record usleep 1
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Captured and wrote 1.540 MB perf.data (2049 samples) ]
  # perf evlist
  kmem:kmalloc
  kmem:kmalloc_node
  kmem:kfree
  kmem:kmem_cache_alloc
  kmem:kmem_cache_alloc_node
  kmem:kmem_cache_free
  # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
  #
  # # Use 'perf script' to get a first approach, select a chunk for then using
  # # with 'perf kmem stat --time'
  #
  # perf script | tail -15
    usleep 9889 [0] 20119.782088:  kmem:kmem_cache_free: (selinux_file_free_security+0x27) call_site=ffffffffb936aa07 ptr=0xffff888a1df49fc0
      perf 9888 [3] 20119.782088:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
      perf 9888 [3] 20119.782089: kmem:kmem_cache_alloc: (jbd2__journal_start+0x72) call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
      perf 9888 [3] 20119.782090:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
      perf 9888 [3] 20119.782090: kmem:kmem_cache_alloc: (jbd2__journal_start+0x72) call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
    usleep 9889 [0] 20119.782091: kmem:kmem_cache_alloc: (__sigqueue_alloc+0x4a) call_site=ffffffffb90ad33a ptr=0xffff8889f071f6e0 bytes_req=160 bytes_alloc=160 gfp_flags=GFP_ATOMIC|__GFP_NOTRACK
      perf 9888 [3] 20119.782091:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
      perf 9888 [3] 20119.782093:  kmem:kmem_cache_free: (__sigqueue_free.part.17+0x33) call_site=ffffffffb90ad3f3 ptr=0xffff8889f071f6e0
      perf 9888 [3] 20119.782098: kmem:kmem_cache_alloc: (jbd2__journal_start+0x72) call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
      perf 9888 [3] 20119.782098:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
      perf 9888 [3] 20119.782099: kmem:kmem_cache_alloc: (jbd2__journal_start+0x72) call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
      perf 9888 [3] 20119.782100: kmem:kmem_cache_alloc: (alloc_buffer_head+0x21) call_site=ffffffffb9287cc1 ptr=0xffff8889b12722d8 bytes_req=104 bytes_alloc=104 gfp_flags=GFP_NOFS|__GFP_ZERO
      perf 9888 [3] 20119.782101:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
      perf 9888 [3] 20119.782102: kmem:kmem_cache_alloc: (jbd2__journal_start+0x72) call_site=ffffffffb9333b42 ptr=0xffff888bdf1a39c0 bytes_req=48 bytes_alloc=48 gfp_flags=GFP_NOFS|__GFP_ZERO
      perf 9888 [3] 20119.782103:  kmem:kmem_cache_free: (jbd2_journal_stop+0x1a1) call_site=ffffffffb9334581 ptr=0xffff888bdf1a39c0
  #
  # # stats for the whole perf.data file, i.e. no interval specified
  #
  # perf kmem stat

  SUMMARY (SLAB allocator)
  ========================
  Total bytes requested: 172,628
  Total bytes allocated: 173,088
  Total bytes freed:     161,280
  Net total bytes allocated: 11,808
  Total bytes wasted on internal fragmentation: 460
  Internal fragmentation: 0.265761%
  Cross CPU allocations: 0/851
  #
  # # stats for an end open interval, after a certain time:
  #
  # perf kmem stat --time 20119.782088,

  SUMMARY (SLAB allocator)
  ========================
  Total bytes requested: 552
  Total bytes allocated: 552
  Total bytes freed:     448
  Net total bytes allocated: 104
  Total bytes wasted on internal fragmentation: 0
  Internal fragmentation: 0.000000%
  Cross CPU allocations: 0/8
  #

Signed-off-by: David Ahern <dsahern@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1480439746-42695-6-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-01 13:03:02 -03:00

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perf-kmem(1)
============
NAME
----
perf-kmem - Tool to trace/measure kernel memory properties
SYNOPSIS
--------
[verse]
'perf kmem' {record|stat} [<options>]
DESCRIPTION
-----------
There are two variants of perf kmem:
'perf kmem record <command>' to record the kmem events
of an arbitrary workload.
'perf kmem stat' to report kernel memory statistics.
OPTIONS
-------
-i <file>::
--input=<file>::
Select the input file (default: perf.data unless stdin is a fifo)
-v::
--verbose::
Be more verbose. (show symbol address, etc)
--caller::
Show per-callsite statistics
--alloc::
Show per-allocation statistics
-s <key[,key2...]>::
--sort=<key[,key2...]>::
Sort the output (default: 'frag,hit,bytes' for slab and 'bytes,hit'
for page). Available sort keys are 'ptr, callsite, bytes, hit,
pingpong, frag' for slab and 'page, callsite, bytes, hit, order,
migtype, gfp' for page. This option should be preceded by one of the
mode selection options - i.e. --slab, --page, --alloc and/or --caller.
-l <num>::
--line=<num>::
Print n lines only
--raw-ip::
Print raw ip instead of symbol
--slab::
Analyze SLAB allocator events.
--page::
Analyze page allocator events
--live::
Show live page stat. The perf kmem shows total allocation stat by
default, but this option shows live (currently allocated) pages
instead. (This option works with --page option only)
--time::
Only analyze samples within given time window: <start>,<stop>. Times
have the format seconds.microseconds. If start is not given (i.e., time
string is ',x.y') then analysis starts at the beginning of the file. If
stop time is not given (i.e, time string is 'x.y,') then analysis goes
to end of file.
SEE ALSO
--------
linkperf:perf-record[1]